#include<stdio.h>
int main()
{
    int y, m;
    printf("Input year,month:\n");
    scanf_s("%d,%d", &y, &m);
    switch (m)
    {
    case 1:
    case 3:
    case 5:
    case 7:
    case 8:
    case 10:
    case 12:
        printf("31 days\n");
        break;
    case 4:
    case 6:
    case 9:
    case 11:
        printf("30 days\n");
        break;
    case 2:
        if (y % 4 == 0 && y % 100 != 0 || y % 400 == 0)
            printf("29 days\n");
        else
            printf("28 days\n"); break;
    default:
        printf("Input error!\n");
    }
    return 0;
}